This invention concerns the preparation of oxacaprolactams by hydrogenation of cyanoalkoxyalkanoates and hydrolysis of the resulting amide-ester. In particular, this invention concerns 3-oxacaprolactams and their preparation.
The 3-oxacaprolactams of this invention have the formula ##STR1## wherein each R.sup.1 is hydrogen or methyl. Compounds having this formula can be polymerized by either anionic polymerization or hydrolytic polymerization to prepare low molecular weight hydrophilic polyamides. These low molecular weight polymers have a relatively low melting point, and at room conditions are sticky, rubbery materials useful as reuseable adhesive caulking agents.
Caprolactam has been obtained by the dehydrogenation of cyclohexanol to cyclohexanone which is then converted to the oxime and rearranged to form the lactam: ##STR2## The lactam, containing a seven-membered ring, can be converted to a linear polymer by heating with a trace of water: ##STR3## The polymer of caprolactam is nylon-6.
Various polyamides can be polymerized or copolymerized to prepare fibers having different properties. For example, German Published Offenlegungstag No. 2,454,118 (May 15, 1975) describes a hydrophilic polyamide prepared by copolymerizing adipic acid and a diamine having the structure EQU --CH.sub.2 --O--(CH.sub.2).sub.3 --NH.sub.2).sub.2.
The diamine was prepared by cyanoethylation of ethylene glycol followed by hydrogenation. The hydrophilicity of the polymer is likely due to the presence of oxygen in the recurring unit.